时速120~250 km市域铁路桥梁段轮轨环境噪声空间分布特性研究

Research on the Spatial Distribution Characteristics of Environmental Noise Caused by Wheel Rail Excitation on Bridges of Suburban Railway at the Speed of 120~250 km/h

采用2.5维边界元方法建立市域铁路桥梁段的声场传播预测模型,考虑近场声学边界(如车体、轨道板、防撞墙和声屏障)对声源的影响,研究轮轨引起的环境噪声在空间上的分布特性。研究结果表明,环境噪声满足随-alg(d)的衰减规律,其中,衰减系数a随着车速增大而增大,1 h等效A声级的衰减系数低于列车通过时间等效A声级的衰减系数;当环境场点距离轨道中心线较远时,评价点高度对轮轨辐射噪声声压级影响会减弱;环境场点距轨面的高度越高,越容易超过标准限值,故在轨道两旁规划建筑时,建筑距轨道中心线的距离应随着建筑高度增加而增大;列车运行速度越高,声屏障插入损失也会越大;声屏障较矮时,其插入损失会随场点高度增大而快速减小,当声屏障达到一定高度后,声屏障高度对插入损失的增益效果会快速降低,故选择声屏障时,应兼顾降噪效果和经济性。

In this paper, a 2.5-dimensional boundary element method was used to establish the sound field propagation prediction model in bridge sections of urban railway. Influences of the near-field acoustic boundary such as car body, track slab, anti-collision wall and sound barrier on the sound source were discussed, and the noise distribution in space was studied. The research results show that the environmental noise satisfies the attenuation law with-alg(d), in which the attenuation coefficient a increases with the increase of the vehicle speed, and the attenuation coefficient of 1 h equivalent A-weighted sound pressure level is lower than that of the equivalent sound A in the period of the train passing by. When the environmental field point is far from the track centerline, the influence of the height of the evaluation point on the wheel-rail deduced sound pressure level will be weakened. The higher the height of the environmental field point from the track surface, the easier it is for the noise to exceed the standard limit. Therefore, when planning buildings beside railways, the distance between the building and the track centerline should increase with the increase of the building height. The insertion loss of the sound barrier will increase with the increase of the train speed. When the sound barrier is low, the insertion loss will decrease rapidly with the increase of the field point height, and when the height of the sound barrier reaches a certain number, the gain effect of the sound barrier height on the insertion loss will decrease rapidly. Therefore, noise reduction effect and economic benefit should be considered simultaneously in the selection of sound barrier.